Most people haven't heard of QNX Software, though they've likely come in contact with it. The real-time operating system is used where software failure can lead to catastrophic consequences, even death - from high-speed trains to air traffic control towers to highway toll systems. It's also used in more than 100 different types of cars on the road.

As amazing as this seems, it is entirely feasible to have elevators with absolutely no computer hardware or software involved: most elevators you use have zero computer hardware involved, in fact. It is very simple (comparatively speaking) to build decent elevators that are very reliable with zero computer stuff, as there's many ways it can be done with simpler electromechanical hardware.

Most modern elevators use microcontrollers, we had some old ones at work who were relais based (open rack with clicking things alover) quite relyable. but they don't live forever...
Modern ones include things like automatic leveling, smoother rides and in larger buildings some clever behaviour of the elevators can be usefull.
Using Microcontrollers with a couple of input, outputs
and a program saves a lot of additional wires and relais.